Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Question on Singular Extension

Author: Andrew

Date: 06:45:27 06/23/99

Go up one level in this thread


On June 23, 1999 at 09:35:09, William Bryant wrote:

>As I understand the use of Singular extensions,
>     when, after generating all the _legal_ moves, there is only one move to be
>     made by the side on move, extend 1 ply.

What you describe here has nothing to do with SE... it's most commonly named
'one reply extension'....

>
>Since you only extend a maximum of 1 ply at any node, if the King is in check,
>     or any other extensions are also triggered you would be extending anyway
>     and this only extends this branch of the tree when it is the only
>     condition extending the search.
>
>To generate legal moves, you must check each move to see if it places the King
>     in danger of being captured, a procedure that I do at present in my
>     MakeMove() function.  The difference being, that it takes more time to
>     check for legality when generating the moves than it does in MakeMove()
>     because cutoffs keep you from making and unmaking all the moves.

You may do legality testing only when in check - it will narrow 'one reply
extension' slightly, but will not slow you down.
>
>Now my question, is the extra time it takes to generate legal vs. pseudolegal
>     moves made up in the search by the singular extension during those
>     positions when nothing else would have triggered an extension in the
>     search anyway?
>
>Am I missing something?
>
>Thank you.
>
>William
>wbryant@ix.netcom.com

-Andrew-



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.